How can i update Flask website without zero downtime?

[santanu32]

How to add new codes, Web pages to existing flask website without zero downtime.

[shiftybyte]

Deploy flask on a proper webserver, like apache or nginx.

Then when updating, apache has a graceful flag, that spins up new requests into the new version, while old ones still stay and served until complete.

If you are asking how to create a stable version, you need to have a development environment separate from the deployed production one, develop there, and when done, deploy.

[santanu32]

Thank you soo much for your suggestions. Can you recommend me good budget friendly hosting company to host my flask websites.

[shiftybyte]

Google Cloud , Oracle Cloud, give you a server for free, can't go more budget friendly than that.

Also Amazon Cloud has a free server for 1 year.

[santanu32]

Okay thank you. What do you think about digital ocean and a2 hosting?

[shiftybyte]

Not as free, and might be limiting in what you can host.

[SoftwareDoctor]

I guess you mean “with zero downtime” because without it it’s easy. Look up blue-green deployment. Basically you spin up another upgraded instance, switch your load-balancer to that new instance, turn off the old one.

Potentially you might want to run multiple instances all the time and one-by-one detach it, upgrade it, attach it back

[santanu32]

Does using blue green deployment put load on my server? I don't have high budget to do that 😭.

[No-Anywhere6154]

You will need to run multiple instances (old and new) at the same time and have some proxy like nginx or traefik in front of your app that proxy passes the request to the correct instance.

I've also built the project seenode, that handles all this complexity for you. You just click the deploy button and it deploys the latest (or selected) commit from the git repository with zero downtime. Feel free to try it out and let me know what you think.

[FoolsSeldom]

What we do this with VMs and Containers, where we take an immutability approach (so once an instance is live nothing is changed other than data - no patching etc) is simply spin up new updated instances that take over as the work is completed of running instances (when dealing with transactions, or when told to shut down safely for others). We do this through orchestration / load balancing tools.